DXR Drainback
Page 16
PIPING THROUGH THE ROOF
Penetrations of the building through which piping or wiring is passed shall not reduce or impair the function of the
enclosure. Penetrations through walls or other surfaces shall not allow intrusion by insects and/or vermin. Required
roof penetrations shall be made in accordance with applicable codes and also by practices recommended by the
National Roofing Contractors Association. When penetrations are required in structural members to accompany
passage of solar components, those modified structural members shall comply with local building codes.
Penetrations through fire-rated assemblies etc. shall not reduce the building's fire resistance required by local codes,
ordinances and applicable standards.
One inch holes are drilled through the roof on the same plane as the supply and return header nipples. Do not drill
the hole above the supply header of the collector. This will prevent the collector from draining. Placing the hole
below the supply header is acceptable, but it is more aesthetic if it is located on the same plane. A copper flashing is
placed around the hole with its base cemented to the roof and its upper edges slid under the adjoining shingle. The
copper tube supply and return line is then pushed up through the hole in the flashing. A “coolie cap” is then slid over
the copper tube till it meets the flashing. After piping to the collectors is completed, the “coolie cap” is soldered to
the copper tube. This allows for expansion and contraction of the copper pipe, while maintaining a rain/snow
barrier. Polybutylene adhesive is then placed on the top and bottom of the flashing, providing a weatherproof seal.
The sensor wire should also be run through the return flashing.
In-roof piping hangers shall provide adequate support and correct pitch (1/4” per foot minimum) of pipes. Supports
for insulated pipes should avoid compressing or damaging the insulation material.
SENSOR MOUNTING AT COLLECTOR
The controller heat sensor is mounted to the nipple outlet of the collector. A stainless steel, screw-type pipe clamp
secures the sensor to the pipe or the sensor can be wedged in the header grommet. When clamped, insure the sensor
is clamped across the flat / compressed portion of the sensor. Clamping across the barrel of the sensor can cause
permanent damage to the sensor. The entire nipple should be wrapped thoroughly with insulating tape so that the
sensor is isolated from the outside air. Sensor interconnect wiring should be 18-22 gauge and rated for outdoor use.
Sensor wire should not be in direct contact with the piping. The sensor wire is to be wrapped to the outside of the
pipe insulation.
Do not run the wires parallel to telephone or power cables. If the sensor wires are located in an area
with strong sources of electromagnetic interference (EMI), shielded cable or twisted pair should be used or the wires
can be run in a grounded metal conduit.
All connections exposed to the weather must be made with waterproof
“outdoor” rated connectors.
Sensor with stainless clamp Sensor wedged in grommet
